Three-Phase DC-AC Inverter with Low Power Dissipation Filter for Photovoltaic-Based Micro-Grid Scale Electric Power System

This paper presents a three-phase DC-AC inverter with a low power dissipation filter for photovoltaic-based micro-grid power system. The traditional LCL and LLCL filters can reduce harmonic disruptions, but they create new problems in terms of a considerable resonance in their fundamental frequency. They also results in lower power output. Therefore, this paper proposes a new filter configuration that can improve power output but does not increase the THD. A comparative study of several filter topologies, including the LCL, LLCL filters and the new filter, is presented in this paper. The simulation results show that the new proposed filter with a H-bridge damper element gives THD of about 0.39% for the output voltage and about 1.98% for output current. The average output voltage amplitude of the filter is about 220V-380V, which is almost similar to its input voltage domain. With those input voltage domain, the proposed filter can deliver about 6.8-7.1kW output power with very impressive power efficiency of about 95%.